At present irrigation systems can be broadly classified into two classes fixed in ground systems (often referred to as solid set systems) and mobile above ground systems.
In general solid set systems are used for horticultural applications, particularly for irrigating very large areas of land, and mobile systems are used for animal farming applications usually for smaller areas of land to minimise set up time. Solid set systems comprise a riser pipe which extends from an in ground supply line and upon which a sprinkler head is located; and mobile systems comprise a string of sprinkler units on skids or pods which are joined by an above ground supply line
A key reason for solid set systems being used in horticulture is that larger animals, such as cattle and pigs, can cause extensive damage to sprinklers left in situ due to the animals' size, weight and frequently curiosity of the animal.
To combat these problems mobile sprinkler systems have been developed to b e used predominantly when a field does not have animals grazing thereon and the sprinklers are simply swapped to a new field as the animals are rotated between fields or they are large enough for the animals not to interfere with them. Some mobile sprinkler systems such as the applicants very successful K-LINE™ sprinklers have a protective pod which surrounds the sprinkler to protect the sprinkler from animals should the sprinklers and animals share a field for a period of time as well as protect the sprinklers from damage when being moved between fields.
However, when grazing large herds on large fields mobile systems suffer from a number of drawbacks including:                Time and labour involved with moving the sprinkler line(s) within a field and/or between fields;        Ensuring proper placement of the pods each time the mobile system is set up to ensure proper coverage of the field with liquid from the sprinkler head occurs.        
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
Throughout this specification, the word “comprise”, or variations thereof such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.